Synthesis And Application Of Cationic Styrene Acrylic Ester Polymer Surface Sizing Agent

Surface sizing is an effective way to increase paper’s water-resistance，and improve theprintability. SAE (styrene acrylic ester) polymer surface sizing agent has many superioritiessuch as simple process and significant effect, so it is the fastest developing and most widelyused in recent years. The purpose of this study was to search out an optimum synthetic process,which can synthesize a new efficient cationic SAE surface sizing agent, by which paper’s waterresistance, surface strength and bursting strength can be improved significantly. Theinnovations of this study mainly reflected in two aspects: One of them was using the starch asthe emulsion stabilizer, overcame the shortcomings of small molecule emulsifiers, andincreased the emulsion effect. The other was taking cationic modification to the traditionalanion type styrene butyl acrylic polymer surface sizing agent, reinforced the bonding betweenthe agent and the fiber, and enhanced the sizing effect.By study on the monomer ratio and emulsifier system, the optimum condition oftraditional anion type styrene butyl acrylic polymer surface sizing agent was explored. Theresults showed that the monomer ratio has great effect on the polymer’s property and sizedpaper’s performance. When the hard monomer’s proportion was80%, product’s comprehensiveperformance would be the best, compared to sized by oxidation starch only, paper’s Cobb valuedecreased by51.8%. Single factor experiment and Orthogonal design was utilized to analyze themain factors in the emulsifier system, the optimum conditions were: amount of emulsifier2%to monomers, amount of starch20%to monomers, revolving speed600r/min, SDS scale0%tototal emulsifier.By comparing different methods of the cationic modification to the polymer surface sizingagent, it was found that the way of combine cationic monomer DMC and cationic starch wouldbe better. The dosage of cationic monomer had great influence on sized paper’s performance,take the cost into account, the appropriate dosage of cationic monomer was3%to totalmonomers. In this condition, sized paper’s Cobb value was31.4g/m2, surface strength was400cm/s, and the bursting strength was450.1kPa, these result were all better than which size byanion surface sizing agent.The appearance of the synthetic cationic SAE surface sizing agent was milky whiteemulsion with blue ray. It’s solid content is27.7%, viscosity is33.8mPa·s, the positive chargedensity0.1546mmol/g, the glass transition temperature is65.8℃. The FT-IR chart illustratedthat the polymer was comprised by all the monomers took part in the reaction. SEM scanning electron micrographs proved that paper sized by oxidized starch being added a certainproportion of cationic surface sizing agent had the best surface morphology, compared to thepapers sized by oxidized starch alone, or the oxidized starch being added the anion surfacesizing agent.During the application research of the cationic styrene acrylic ester polymer surface sizingagent, the author mainly investigated the effects of the surface sizing agent’s dosage and thesizing amount. The result showed: when preparing the surface sizing solution, made thecationic surface sizing agent’s dosage be5%to the dry weight of oxidized starch, paper’scomprehensive performance would be better, and could save cost. In the process of sizing,control the sizing amount to be6g/m2, on the base of cost saving, paper’s water-resistance,surface strength and bursting strength would increase significantly.